This invention relates to tensioning apparatus. It was developed for dual purpose seat structures such as that described in our Patent GB-B-2197628, but it has wider applications.
According to the present invention there is provided tensioning apparatus for a flexible tie that can be pulled out from a spring biased retractor reel when a locking mechanism associated therewith is disengaged, the apparatus comprising an actuator which co-operates with the reel locking mechanism and which has an element around which the tie is entrained, wherein, at a start position of the actuator, the locking mechanism is held disengaged thereby and the tie is withdrawable from the reel to be attached to a workpiece, any slack being taken up by the reel spring, wherein initial movement of the actuator from the start position causes the locking mechanism to engage and wherein further movement of the actuator to a stable finish position tensions the tie.
Usually, the tie will be a belt. For many applications, the actuator will include a pedal, raised in the start position and depressed in the finish position. But the actuator could be powered.
The actuator may include a linkage whose configuration at the finish position gives the actuator its stability at that position.
In addition, or alternatively, there can be a locking device arranged to engage the actuator automatically as it reaches the finish position. This locking device may have a remote release control, particularly if the actuator is a pedal.
A common actuator could govern more than one reel, and this is particularly applicable to wheelchair restraints. Two ties can have hooks to engage low down at the rear or wheelchair frame, and when tensioned the wheelchair will be pulled back firmly against an abutment substantially above axle height of its rear wheels.